Straightening machine with overload release

ABSTRACT

The rolls in one of two rows of rolls in a straightening machine are mounted in supports that extend radially back away from the rolls. Secured to the outer ends of adjusting screws threaded in the rear ends of these supports are pistons disposed in stationary fluid pressure cylinders, in the rear ends of which are slidably mounted rotatable shafts that are connected with the screws. Conduits connected with these cylinders behind the pistons receive fluid pressure to hold the pistons against the front ends of its cylinders. Connected with the conduits are means actuated by an increase in the fluid pressure, caused by excessive pressure of a workpiece against the rolls, for releasing the increased pressure until the excessive pressure is removed. The fluid pressure in the conduits also can be reduced manually to permit the adjusting screws to be turned and to permit the pistons to be quickly moved back in their cylinders to open the roll pass.

" Thompson [75] Inventor: Elbert Gordon Thompson, State College, Pa.

[73] Assignee: Sutton Engineering Company,

Pittsburgh, Pa.

{22] Filed: Dec. 6, 1973 [21] Appl. No.: 422,278

[52} US. Cl 72/245, 72/98, 72/110 [51] Int. Cl. 1321b 33/00 [58] Field of Search 72/98, 100, 101, 110, 245

[56] References Cited UNITED STATES PATENTS 1,382,309 6/1921 Moltrup 72/98 2,987,096 6/1961 McConnell 72/98 3,435,649 4/1969 OBrien 72/245 3,492,850 2/1970 Groppini 72/98 Primary Examiner-Lowell A. Larson [57] ABSTRACT The rolls in one of two rows of rolls in a straightening machine are mounted in supports that extend radially back away from the rolls. Secured to the outer ends of adjusting screws threaded in the rear ends of these supports are pistons disposed in stationary fluid pres sure cylinders, in the rear ends of which are slidably mounted rotatable shafts that are connected with the screws. Conduits connected with these cylinders behind the pistons receive fluid pressure to hold the pistons against the front ends of its cylinders. Connected with the conduits are means actuated by an increase in the fluid pressure, caused by excessive pressure of a workpiece against the rolls, for releasing the increased pressure until the excessive pressure is removed The fluid pressure in the conduits also can be reduced manually to permit the adjusting screws to be turned and to permit the pistons to be quickly moved back in their cylinders to open the roll pass.

7 Claims, 4 Drawing Figures Jan. 7, 1975' Palm Jan. 7, 1975 3,858,425

5 Sheets-Sheet l Patented Jan. 7, 1975 3,858,425

3 Sheets-Sheet 71 Patented Jan. 7, 1975 STRAIGIITENING MACHINE WITI-I QVERLOAD RELEASE It is among the objects of this invention to provide a staightening machine which will maintain a substantially constant pressure on workpieces being straight ened, which will not be damaged by excessive pressure against the rolls, which is fully adjustable and in which the roll pass can be quickly opened and closed. Another object is to provide a hydraulic system for accomplishing the above objects.

The preferred embodiment of the invention is illus trated in the accompanying drawings, in which FIG. Us a fragmentary horizontal section, somewhat diagrammatic;

FIG. 2 is a fluid pressure circuit diagram with one of the valves shown in section, the conduits at the top of the drawing being continuations of the conduits at the bottom of FIG. 1;

FIG. 3 is a fragmentary vertical section of the front end portion of one of the roll support housings; and

FIG. 4 is a cross section taken on the line lV-IV of FIG. 3.

Referring to FIG. I of the drawings, two or more concave rolls 1 disposed in a row are driven continuously by any suitable means. These rolls are mounted in fixed position in the usual manner. Cooperating with these rolls are three or more adjustable concave rolls 2 dis posed in a second row. The rolls in each row are skewed, those in the second row being skewed in an opposite direction from those in the first row so that a round workpiece 3, such as a bar or tube, traveling lengthwise through the roll pass will be rotated on its axis and straightened.

Each adjustable roll 2 in the second row is carried by a fork Son the outer end of a roll support 6 that extends radially away from the roll. The support is cylindrical and extends into a housing 7 adjustable laterally in the framework 8 of the machine. The inner or rear end of the support is formed by a large nut 9, in which an adjusting screw 10 is threaded. A portion of the support is hollow to receive the inner end of the screw. The outer end of the screw is rigidly connected to a piston 11 in an overload cylinder 12 mounted on the rear end of the housing. A screwdown shaft 13 connected by the piston with the screw extends rearwardly out of the cylinder, in which the shaft can slide and be rotated. Suitable means (not shown) are provided for turning the screwdown shaft in order to cause screw 10 to adjust the roll support 6 forward and backward in housing 7.

To permit the angle of the rolls to be adjusted by turning the roll supports on their axis, the front end of each housing 7 is provided with a recess 15, as shown in FIGS. 3 and 4, in which there is a clamping yoke 16 that fits part way around the adjoining roll support. The central part of the yoke is secured to support 6 by a key 17. One projecting end of the yoke is engaged by a shoe 18 on the lower end of a vertical rack bar 19 that extends up through a gear housing 20 mounted on housing 7. A gear in the rear housing meshes with the rack and can be driven through a flexible shaft 21 (FIG. 3) from a suitable drive at the opposite end of the shaft. When .the rack is moved downwardly, it presses down on the underlying end of the yoke and tilts the yoke to turn the roll support counterclockwise as viewed in FIG. 4. To turn the support in the opposite direction, the opposite end of the yoke is engaged by a shoe 22 on the lower end of a piston rod 23 projecting from a fluid pressure clamping cylinder 24 mounted on housing 7. When the rack bar is raised and the piston is forced downwardly, the yoke is tilted to turn the roll support clockwise. After-the desired adjustment has been made, the pressure on the piston is increased so that workpieces traveling through the straightener cannot cause the roll support to turn by moving the piston end of the yoke upwardly.

During straightening, the pistons 11 at the rear ends of the roll support housings are forced tightlyagainst the front ends of their cylinders by fluid pressure behind them. As shown in FIGS. 1 and 2, this pressure is supplied through a first conduit 26 that extends through a pressure intensifier 27 from a motor-driven pump 28, that draws hydraulic fluid froma tank 29, to cylinders 12. The same conduit is connected by conduits 30 (FIG. 1) to the upper ends of clamping cylin ders 24 mounted on the front ends of the roll support housings. In one embodiment of this invention the pump supplies fluid under a pressure of 700 psi to the intensifier, where the pressure is raised to 3,500 psi.

Between the intensifier and the cylinders there is a branch conduit 32 (FIG. 2) that leads to the inlet of a pressure relief valve 33. This valve may take different forms, but since it performs several different functions it may be of the balanced piston relief type. The inlet of such avalve leads into a chamber 34, through which a tubular piston stem 35 extends. This stem normally is pressed downwardly by a coil spring 36 to cause the lower end of the stem to close an outlet port 37 that-is connected by a pipe 38 to tank 29. Rigidly mounted on the stem is a piston 39 having an orifice 40 through it to connect the main chamber, of the valve with a smaller chamber 41 above the piston. This chamber is connected by a vent passage 42 with the outside of the valve housing and with a chamber 43 that leads to the upper end of the piston stem. This last chamber con tains an adjustable spring-pressed valve 44 that normally closes the inlet to the chamber from the vent passage. The vent passage is connected by a pipe 45 to a normally closed control valve 46 that can be operated by solenoid coils 47 and 48.

If for some reason a workpiece traveling through the straightener exerts excessive pressure on the adjustable rolls 2, the pistons 11 at the rear end of housings 7 will be pushed backwardly and will increase the fluid pressure in the first conduit 26 above the pressure normally maintained in it, e.g. 3,500 psi. This will increase the pressure in the main chamber 34 of the relief valve and in the chamber 41 above piston 39. This increased pressure will force the adjustable valve member 44 away from its seat a distance controlled by the setting of the valve and allow fluid to enter chamber 43 and the upper end of the hollow'piston stem 35 and flow down through it to the tank. This will relieve the fluid pressure above the piston so that it can move upwardly to lift the piston stern off its seat and thereby connect the inlet of the valve directly with the tank to maintain pressure in conduit 26 at 3,500 psi. As soon as the increased pressure of the workpiece against the roll has stopped, the movable parts of the relief valve will return to their normal positions, with the fluid pressure in the first and second. conduits remaining at 3,500 psi. Damage to the rolls or other parts of the straightener is prevented by the opening of the relief valve as just described.

When it is necessary to operate the screwdown shafts 13 to adjust the roll pass, the fluid pressure behind pistons 11 should be greatly reduced so that they will not interfere with turning of the screwdowns. However, during the operation of the screwdowns these pistons still should be pressed fairly tightly against the front ends of their cylinders in order that an accurate adjustment can be made. To reduce the fluid pressure behind the pistons, solenoid 47 of control valve 46 is energized in order to shift the valve so that the vent 42 of relief valve 33 will be connected through a pipe 51 with a second adjustable relief valve 52 that is set to open at a much lower pressure, for example 300 psi. With the two valves connected in this manner, the fluid pressure behind pistons 11 will be reduced to 300 psi because fluid from conduit 26 will be allowed to escape from control valve 33 through its outlet 37 and pipe 38 to the tank. The screwdowns then can be operated easily.

The control valve 46 is operated in the same way when it is desired to adjust the angles of the rolls in a counterclockwise direction. Thus, the pressure to the clamping cylinders above the clamping yokes is reduced to 300 psi so that the yokes can be tilted easily by rack bars 19. If the rack bars are raised, shoes 22 will press the adjoining ends of the yokes down to tilt the yokes in a clockwise direction.

It also is desirable to be able to open the roll pass quickly, such as when a workpiece is first delivered to the pass. This is accomplished by energizing the other solenoid 48 at control valve 46 so that the vent of relief valve 33 will be connected through a pipe 54 directly with the tank, thereby allowing the main outlet 37 of that valve to open wide and be connected to the tank, preferably through a 30 psi check valve 55 in pipe 38. This reduces the pressure behind pistons 11 from 3,500 psi to 30 psi. At the same time, high fluid pressure is applied to the front faces of those pistons to move them backwardly in their cylinders as rapidly as possible. For this purpose a conduit 57 is connected to the first conduit 26 between the pump and pressure intensifier 27 and leads to a fourth valve 58 that is connected by a branched conduit 59 with cylinders 12 in front of the pistons. The valve normally closes conduit 57 and connects conduit 59 with the tank through a pipe 60.

Branching off from conduit 57 at the upstream side of valve 58 is an accumulator 61. The pressure in this accumulator is the same as the pump pressure, which in the example given is 700 psi. At the same time that solenoid 48 of the control valve is energized, a solenoid 62 that shifts the fourth valve 58 is energized to connect conduit 57 with the conduit 59 leading to overload cylinders 12. The pressure in the conduit 57 and the accumulator is immediately exerted against the front faces of pistons 11 to drive them backward in their cylinders to open the roll pass.

' It will be seen that the fluid pressure behind pistons 11 and in the top of the clamping cylinders can be reduced by a manually operated control valve 46 and that this valve can likewise be operated along with the additional valve 58 to quickly open the roll pass. While the straightener is operating, the relief valve 33 will automatically open sufficiently to prevent excessive pressure from being exerted against the rolls.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

I. A straightening machine comprising a first row of rolls, a second row of rolls cooperating with those in the first row to form a pass for workpieces to be straightened, supports connected to the second row rolls and extending radially thereof back away from them, means supporting said supports for longitudinal adjustment, adjusting screws threaded in the rear ends of said supports, pistons secured to the rear ends of the screws, stationary fluid pressure cylinders containing said pistons, rotatable shafts slidably mounted in the rear ends of the cylinders and connected with the screws for turning them to adjust said supports, a conduit connected with each cylinder behind its piston, means for supplying fluid under a predetermined high pressure to the conduit to hold the pistons against the front ends of their cylinders, and fluid pressure actuated means connected with said conduit and actuated by an increase in said fluid pressure in the conduit caused by rearward movement of said roll supports and pistons in response to excessive pressure of a workpiece against the rolls in said second row to release said increased fluid pressure until said excessive pressure is removed, whereby to maintain said predetermined pressure substantially constant.

2. A straightening machine according to claim 1, including manually .controlled means for releasing fluid pressure from said pressure-release means to reduce said predetermined pressure to a lower value to permit said shafts to be turned to adjust said roll supports.

3. A straightening machine according to claim 1, including a second conduit connected with each of said cylinders in front of the pistons therein, manually controlled means for releasing fluid pressure from said pressure-release means to reduce said predetermined pressure to a low value, and valve means operated substantially simultaneously therewith for opening said second conduit to said fluid supplying means to thereby move the pistons rearwardly in their cylinders.

4. A straightening machine according to claim 3,including a fluid pressure intensifier disposed in the firstmentioned conduit between said pressure-release means and the'inlet of said second conduit, and an accumulator connected with said second conduit upstream from said valve means for suddenly supplying fluid pressure to the fronts of said pistons when said valve means is operated.

5. A straightening machine according to claim 1, including means for turning each roll support on the adjusting screw therein to adjust the roll angle, fluid pressure operated means for clamping said supports in fixed positions, a third conduit connecting the firstmentioned conduit with said clamping means to normally apply said predetermined fluid pressure thereto, and manually controlled means for releasing fluid pressure from said pressure-release means to reduce said predetermined pressure against said clamping means to a lower value, whereby said roll supports can be turned.

6. A straightening machine according to claim 1, in which said pressure-release means is a first relief valve provided with an inlet and an outlet and a vent, the straightener also including a normally closed control valve for said vent, means for'actuating said control valve to open said vent to drain, a second relief valve it in one direction, and fluid pressure operated means engaging the opposite end of the yoke for tilting it in the opposite direction and for clamping it in fixed posi- I tion, and manually operated means for reducing fluid pressure at said fluid pressure operated means to a lower value to reduce the clamping force on said yokes. l= =l 

1. A straightening machine comprising a first row of rolls, a second row of rolls cooperating with those in the first row to form a pass for workpieces to be straightened, supports connected to the second row rolls and extending radially thereof back away from them, means supporting said supports for longitudinal adjustment, adjusting screws threaded in the rear ends of said supports, pistons secured to the rear ends of the screws, stationary fluid pressure cylinders containing said pistons, rotatable shafts slidably mounted in the rear ends of the cylinders and connected with the screws for turning them to adjust said supports, a conduit connected with each cylinder behind its piston, means for supplying fluid under a predetermined high pressure to the conduit to hold the pistons against the front ends of their cylinders, and fluid pressure actuated means connected with said conduit and actuated by an increase in said fluid pressure in the conduit caused by rearward movement of said roll supports and pistons in response to excessive pressure of a workpiece against the rolls in said second row to release said increased fluid pressure until said excessive pressure is removed, whereby to maintain said predetermined pressure substantially constant.
 2. A straightening machine according to claim 1, including manually controlled means for releasing fluid pressure from said pressure-release means to reduce said predetermined pressure to a lower value to permit said shafts to be turned to adjust said roll supports.
 3. A straightening machine according to claim 1, including a second conduit connected with each of said cylinders in front of the pistons therein, manually controlled means for releasing fluid pressure from said pressure-release means to reduce said predetermined pressure to a low value, and valve means operated substantially simultaneously therewith for opening said second conduit to said fluid supplying means to thereby move the pistons rearwardly in their cylinders.
 4. A straightening machine according to claim 3, including a fluid pressure intensifier disposed in the first-mentioned conduit between said pressure-release means and the inlet of said second conduit, and an accumulator connected with said second conduit upstream from said valve means for suddenly supplying fluid pressure to the fronts of said pistons when said valve means is operated.
 5. A straightening machine according to claim 1, including means for turning each roll support on the adjusting screw therein to adjust the roll angle, fluid pressure operated means for clamping said supports in fixed positions, a third conduit connecting the first-mentioned conduit with said clamping means to normally apply said predetermined fluid pressure thereto, and manually controlled means for releasing fluid pressure from said pressure-release means to reduce said predetermined pressure against said clamping means to a lower value, whereby said roll supports can be turned.
 6. A straightening machine according to claim 1, in which said pressure-release means is a first relief valve provided with an inlet and an outlet and a vent, the straightener also including a normally closed control valve for said vent, means for actuating said control valve to open said vent to drain, a second relief valve set to open at a lower pressure than said first relief valve, and means for actuating the control valve to connect said vent with said second relief valve.
 7. A straightening machine according to claim 1, including a housing for each of said roll supports, a yoke, extending across each roll support and attached thereto, means engaging one end of the yoke for tilting it in one direction, and fluid pressure operated means engaging the opposite end of the yoke for tilting it in the opposite direction and for clamping it in fixed position, and manually operated means for reducing fluid pressure at said fluid pressure operated means to a lower value to reduce the clamping force on said yokes. 